Fix 3D compilation.

src/geometry/contact_generator/pfm_pfm_contact_generator.rs

@@ -138,7 +138,7 @@ impl MaybeSerializableData for PfmPfmContactManifoldGeneratorWorkspace {
         ))
     }
 
-    fn clone(&self) -> Box<MaybeSerializableData> {
+    fn clone_dyn(&self) -> Box<MaybeSerializableData> {
         Box::new(self.clone())
     }
 }

src/geometry/polyhedron_feature3d.rs

@@ -5,7 +5,7 @@ use crate::utils::WBasis;
 use na::Point2;
 use ncollide::shape::Segment;
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct PolyhedronFace {
     pub vertices: [Point<f32>; 4],
     pub vids: [u8; 4], // Feature ID of the vertices.